Slugs! Of course.Allow me to answer yet another tech question for you Donnie. Slug is a slang term used for piston. The question was what happened to the plan to get a new set of pistons.
What would I do without you, you Nasty thang. :tongue:
Lots of blowby
- Thread starter Alky V6
- Start date
What would I do without you, you Nasty thang. :tongue:
My present thinking about my blowby problem is that without the proper amount of crankcase breathing in place (only one 1/2" hole to relieve bottom end pressure buildup ), the rings were most likely lifting or fluttering when the crankcase pressure built up to a high enough level. For the cam plug to be blown out the way it did in late 2009, the pressure in the bottom end had to be a fair amount. Since rings need a proper pressure differential between above and below the rings to seal properly, it's not a far stretch to imagine that the rings didn't like the improper pressure differential that was building as the bottom end pressure continued to climb throughout the run.
The new -8 hose that I added to the timing cover now steps to a -12 after a foot or so. The hose then continues to the new catch tank.
During the next teardown of the engine, I will be adding more holes to the front of the block for more breathing to the lifter valley area. I don't want to drill holes in the lifter valley for stand off tubes. I'd rather leave the lifter valley solid for strength reasons. A -16 hose will be used to relieve the pressure from the lifter valley to the new catch tank.
I can see three different ways that the buildup of crankcase pressure was hurting me. First, as I explained above, the build up of pressure compromised the sealing ability of the rings, which led to an increasing level of blowby and buildup of bottom end pressure as the run continued. Second, the increase in blowby past the rings was affecting power levels on top of the piston. And third, the excessive bottom end pressure created a pressure differential above and below the piston that hurt performance. When pressure in the crankcase is kept low, the piston has an easier time being pushed down the cylinder when combustion takes place.
That is a fair amount of hp that's being lost due to improper bottom end breathing capacity.
), the rings were most likely lifting or fluttering when the crankcase pressure built up to a high enough level. For the cam plug to be blown out the way it did in late 2009, the pressure in the bottom end had to be a fair amount. Since rings need a proper pressure differential between above and below the rings to seal properly, it's not a far stretch to imagine that the rings didn't like the improper pressure differential that was building as the bottom end pressure continued to climb throughout the run.The new -8 hose that I added to the timing cover now steps to a -12 after a foot or so. The hose then continues to the new catch tank.
During the next teardown of the engine, I will be adding more holes to the front of the block for more breathing to the lifter valley area. I don't want to drill holes in the lifter valley for stand off tubes. I'd rather leave the lifter valley solid for strength reasons. A -16 hose will be used to relieve the pressure from the lifter valley to the new catch tank.
I can see three different ways that the buildup of crankcase pressure was hurting me. First, as I explained above, the build up of pressure compromised the sealing ability of the rings, which led to an increasing level of blowby and buildup of bottom end pressure as the run continued. Second, the increase in blowby past the rings was affecting power levels on top of the piston. And third, the excessive bottom end pressure created a pressure differential above and below the piston that hurt performance. When pressure in the crankcase is kept low, the piston has an easier time being pushed down the cylinder when combustion takes place.
That is a fair amount of hp that's being lost due to improper bottom end breathing capacity.
The new catch tank has three -12 inlets and one -16 inlet. There are three chambers filled with copper wool and Scotchbrite padding to help collect the oil and water vapor from the blowby.
There are two -12 outlets leading to the vacuum pump. I put in two fittings in case I went with a new vacuum pump with two -12 inlets.
After the two outlets, there is a low sump section to collect oil and water that separates from the blowby. A petcock to drain the sump is at the bottom of the tank.
Above the sump is a one-way trap door. The trap door allows flow out of the tank if pressure begins to build above outside atm, but closes shut if the pressure is equal to atmosphere or below atm if the vacuum pump can pull it down that far.
Above the trap door are two typical K&N catch tank breathers.
This new catch tank setup will require me to disconnect the line leading to the vacuum pump periodically to spray lube into the hose to lubricate the vacuum pump, since the blowby tank is doing such a good job of pulling all the oil out of the blowby. Normally, the vacuum pump receives lubrication from the oil mist that is in the blowby. Now the vacuum pump will periodically receive a lighter spray lube instead of the constant heavier engine oil mist. That should allow the vanes in the pump to go through their action easier and maybe allow the pump to be more efficient.
With the line removed from the tank and the engine idling, the vacuum pump does pull well at the inlet of the hose.
There are two -12 outlets leading to the vacuum pump. I put in two fittings in case I went with a new vacuum pump with two -12 inlets.
After the two outlets, there is a low sump section to collect oil and water that separates from the blowby. A petcock to drain the sump is at the bottom of the tank.
Above the sump is a one-way trap door. The trap door allows flow out of the tank if pressure begins to build above outside atm, but closes shut if the pressure is equal to atmosphere or below atm if the vacuum pump can pull it down that far.
Above the trap door are two typical K&N catch tank breathers.
This new catch tank setup will require me to disconnect the line leading to the vacuum pump periodically to spray lube into the hose to lubricate the vacuum pump, since the blowby tank is doing such a good job of pulling all the oil out of the blowby. Normally, the vacuum pump receives lubrication from the oil mist that is in the blowby. Now the vacuum pump will periodically receive a lighter spray lube instead of the constant heavier engine oil mist. That should allow the vanes in the pump to go through their action easier and maybe allow the pump to be more efficient.
With the line removed from the tank and the engine idling, the vacuum pump does pull well at the inlet of the hose.
I have a boost controller curve that is controlling the boost very well. The short term goal with the boost is to see if the 1-2 will take more boost with the new harder launch and the change to the 3.73:1 gears. This Saturday I'll find out if the blowby catch tank has changed the boost curve throughout the run.
Correction
The hose at the timing cover was upgraded from a -8 to a -10 when I put the step up to a -12 into the hose. I couldn't make it -12 all the way to the timing cover due to space constraints. So the hose leaves the timing cover at -10 and after a foot or so, steps up in size to a -12, and on to the catch tank.
The hose at the timing cover was upgraded from a -8 to a -10 when I put the step up to a -12 into the hose. I couldn't make it -12 all the way to the timing cover due to space constraints. So the hose leaves the timing cover at -10 and after a foot or so, steps up in size to a -12, and on to the catch tank.
I found a link to some pics someone took of the car at the Coronado Speed Fest Weekend a few weeks ago. They're better pics of the catch tank than I could take myself in the shop with the poor lighting. I had just finished the tank before that car show.
SoCal Muscle - View Single Post - Coronado speedfest picture thread
SoCal Muscle - View Single Post - Coronado speedfest picture thread
Squid4life
Well-Known Member
- Joined
- Jul 5, 2004
Donnie, looks great and as usual, beautiful fab work. You definitely have some mad scientist skills!
Ran the car today. Some amazing results.
No more smoke at the end of the pass.
No oil trying to leave the breather filters. All is dry.
Boost level is steady on the top end, and is about 1 psi higher.
No oil film in the exhaust pipe.
Actually, I am surprised things turned out so well. Bottom line,... proper bottom end breathing capacity is VERY IMPORTANT.
No more smoke at the end of the pass.
No oil trying to leave the breather filters. All is dry.
Boost level is steady on the top end, and is about 1 psi higher.
No oil film in the exhaust pipe.
Actually, I am surprised things turned out so well. Bottom line,... proper bottom end breathing capacity is VERY IMPORTANT.
vacuum 6
I have chuckers
- Joined
- Jan 6, 2006
